Enduro Resource Partners LLC Receives $200 Million Equity Commitment from Riverstone Holdings

Fort Worth, Texas and New York, NY (May 4, 2010) – The Riverstone/Carlyle Global Energy and Power Funds, a group of energy-focused private equity funds managed by Riverstone Holdings LLC (“Riverstone”), announced today that, together with a Fort Worth, Texas based private investor group and management, it has committed $200 million to Enduro Resource Partners LLC (“Enduro” or “the Company”). Enduro, a private company based in Fort Worth, will be led by a team of experienced and successful oil and gas professionals including Jon S. Brumley (“Jonny Brumley”) and John Arms. Riverstone also announced that I. Jon Brumley (“Jon Brumley”) will be a significant investor, Board Member and advisor to the Company.

Enduro’s founders formerly led the executive team of Encore Acquisition Company (“Encore”, formerly NYSE: “EAC”) from 1998 until 2010. Encore was acquired by Denbury Resources (NYSE: “DNR”) in March of 2010 for $4.5 billion. Jonny Brumley acted as CEO of Encore from 2006 until the Denbury acquisition, during which time Encore grew production by 40%. John Arms, formerly Senior Vice President of Acquisitions at Encore, has managed over $1.2 billion in oil and gas property acquisitions. These property purchases were the backbone of Encore’s significant growth in production and reserves. From 1998 –2006, Encore was led by Jon Brumley. Prior to forming Encore, Jon Brumley was the CEO of Southland Royalty Company, a Co-Founder of Cross Timbers Oil (now XTO Energy), and the CEO of MESA, Inc. (now Pioneer). Kim Weimer, another senior executive from Encore, will be Enduro’s Chief Financial Officer.

Enduro will concentrate its efforts on acquiring and developing long-lived oil and gas properties in the onshore United States This management team has a successful track record acquiring, producing and finding oil and gas in a diverse set of producing basins. Their footprint extends from South Texas to Montana.

Jonny Brumley, CEO, said “We are delighted to partner with Riverstone in the creation of Enduro. Riverstone’s knowledge of the energy industry, and in particular the exploration and production sector, will be instrumental in helping us create significant value for investors. We believe Riverstone is the ideal partner for this new venture.”

Pierre Lapeyre and David Leuschen, Co-Founders of Riverstone, added “We’ve known and worked with the Enduro management team for over a decade, and are thrilled to partner with them on this new venture. The team is one of the most successful, respected and skilled in the industry, and we believe they will once again deliver exceptional results.”

About Riverstone Holdings LLC
Riverstone Holdings LLC, an energy and power-focused private equity firm founded in 2000, has approximately $17 billion under management across six investment funds, including the world’s largest renewable energy fund. Riverstone conducts buyout and growth capital investments in the midstream, exploration & production, oilfield services, power and renewable sectors of the energy industry. With offices in New York, London and Houston, the firm has committed approximately $13.6 billion to 69 investments in North America, Latin America, Europe and Asia. For more information, visit www.riverstonellc.com.